Since man first began to transform timber into lumber, it became obvious that the lumber needed to be dried prior to being used. In earlier times, quite often cut lumber would simply be stacked in tee-pee fashion about the trunk of a convenient tree. With the advent of saw mills, the amount of lumber that could be cut at one location substantially increased and stacking the lumber in rows and layers became a common practice. This accomplished two things, first, stacked lumber requires much less space for storage and secondly, it generally reduces warpage due to drying. This stacking process at saw mills and lumber yards was a laborious task generally requiring at least two men with at least some skill in order to arrange the stacks in such a manner that air could circulate therethrough to expedite drying and to reduce the possibility of rot which would quickly occur in a tightly packed stack of green or wet lumber.
In more recent years, various devices and apparatus have been developed to aid in the stacking and handling of lumber. These have included sorting devices and conveyors as well as apparatus for stacking the lumber. Some of these last mentioned machines have had incorporated thereinto means for inserting spacer sticks between the layers of lumber. These stick inserters or layers have almost invariably been integrally incorporated into the lumber stacking device with which they are associated and are integrally connected thereto and dependent thereon to the point they are unusable except with the machine they are specifically designed for use in conjunction with.
The majority of the lumber stackers in use today, however, do not have built-in stick layers or inserters but simply rely on manual labor to place the sticks between the layers before the next layer is stacked. This manual stick laying is inaccurate and random at best, requires labor with relatively good coordination and dexterity, and is generally the one bottle necks in operation that controls the amount of lumber which can be stacked in any given time period.
In the integral lumber stacking and stick inserting devices mentioned above, the one requirement for proper operation is that the sticks contained within the hopper be for all practical purposes straight with no warps, twists or bows therein. Whenever a stick is more than a few millimeters out of true, the same will jam the logging mechanism causing the entire machine to be shut down until the warped stick can be removed and discarded. Since most integral stick feeds are gravity fed from a hopper, the offending stick is invariably at the bottom of the pile which makes it not only difficult and time consuming to remove but can on occasion be dangerous to the person removing the same. When using hand layed sticks, the warp problem is not as critical; however, proper locational alignment on the stack is approximate at best and uniformity is for all practical purposes impossible.